On Fri, Sep 21, 2007 at 02:36:50PM +0100, Maciej W. Rozycki wrote: > On Fri, 21 Sep 2007, Andrew Morton wrote: > > > It would be useful to have some basic information like: Which kernel > > version was this found in? Which kernel version last worked? > > The kernel used was a 2.6.23-rc5 snapshot from Sep 4th, 2007 taken from > the linux-mips.org tree (as stated by the revision of the patch provided). > There is no version that can be considered working as the change to add > the printk() to register_console() went in before drivers/serial/zs.c was > added and the old drivers/tc/zs.c driver might have been to sloppy to > handle such bits as the transmitter enable properly. I may investigate. > > Chances are nobody tried any version of the kernel from the period > between the printk() was added and drivers/tc/zs.c removed with the > DECstation; I have not. > > Anyway, I did confirm keeping the transmitter enabled all the time makes > the problem go away. I suspect the correct fix for this is to take the fix in the ARM tree for serial_core's console initialisation, and ensure that zs.c handles the power management of the port (enabling/disabling transmitter) in the power management callback. You can find the fix in the mbox archive: http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cut/arm:devel.mbox -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: - To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html